Wirt made a very interesting exposition, but I would like to add one
small point.  He refers to "biocentric".  Whose "center"  There could
be life forms (perhaps not based on carbon?) that we can't now imagine.
We have certainly come a long ways in the past 200 years in our
understanding
of physical phenomena.  If someone had described radio waves back then
they
would have been tagged a crack pot.  We think of hydrocarbon based
biology.  Do we KNOW that's all there is?

Nick D.